STANDARD URBAN STORM WATER MITIGATION PLAN FOR LOS ANGELES ... · Area of Ecological Significance by the County of Los Angeles (Los Angeles County Significant Areas Study, Los Angeles

FinalApproved – Regional Board Executive OfficerMarch 8, 2000.

STANDARD URBAN STORM WATER MITIGATION PLAN

FOR LOS ANGELES COUNTY AND CITIES IN LOS ANGELES COUNTY

FinalApproved – Regional Board Executive OfficerMarch 8, 2000

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LOS ANGELES COUNTY URBAN RUNOFF AND STORM WATER NPDES PERMIT

STANDARD URBAN STORM WATER MITIGATION PLAN

BACKGROUNDThe municipal storm water National Pollutant Discharge Elimination System (NPDES)permit (Los Angeles County Permit) issued to Los Angeles County and 85 cities(Permittees) by the Los Angeles Regional Water Quality Control Board (RegionalBoard) on July 15, 1996, requires the development and implementation of a programaddressing storm water pollution issues in development planning for private projects. The same requirements are applicable to the City of Long Beach under its separatemunicipal storm water permit (City of Long Beach MS4 Permit), which was issued onJune 30, 1999.

The requirement to implement a program for development planning is based on, federaland state statutes including: Section 402 (p) of the Clean Water Act, Section 6217 ofthe Coastal Zone Act Reauthorization Amendments of 1990 (“CZARA”), and theCalifornia Water Code. The Clean Water Act amendments of 1987 established aframework for regulating storm water discharges from municipal, industrial, andconstruction activities under the NPDES program. The primary objectives of themunicipal storm water program requirements are to:

1. Effectively prohibit non-storm water discharges, and2. Reduce the discharge of pollutants from storm water conveyance systems

to the Maximum Extent Practicable (MEP statutory standard).

The Standard Urban Storm Water Mitigation Plan (SUSMP) was developed as part ofthe municipal storm water program to address storm water pollution from newDevelopment and Redevelopment by the private sector. This SUSMP contains a list ofthe minimum required Best Management Practices (BMPs) that must be used for adesignated project. Additional BMPs may be required by ordinance or code adopted bythe Permittee and applied generally or on a case by case basis. The Permittees arerequired to adopt the requirements set herein in their own SUSMP. Developers mustincorporate appropriate SUSMP requirements into their project plans. Each Permitteewill approve the project plan as part of the development plan approval process andprior to issuing building and grading permits for the projects covered by the SUSMPrequirements.


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All projects that fall into one of seven categories are identified in the Los AngelesCounty MS4 Permit as requiring SUSMPs. These categories are:

• Single-Family Hillside Residences• 100,000 Square Foot Commercial Developments• Automotive Repair Shops• Retail Gasoline Outlets• Restaurants• Home Subdivisions with 10 to 99 housing units• Home Subdivisions with 100 or more housing units

The Regional Board Executive Officer has designated two additional categories subjectto SUSMP requirements for the Los Angeles County MS4 Permit. These categories are:

• Location within or directly adjacent to or discharging directly to an environmentally sensitivearea, and

• Parking lots 5,000 square feet or more or with 25 or more parking spaces and potentiallyexposed to storm water runoff

The City of Long Beach permit requires SUSMP for the following categories only: (i) 10-99 home subdivisions; (ii) 100 or more subdivisions; (iii) 100,000 or more square footcommercial developments; and (iv) Projects located adjacent to or discharging toenvironmentally sensitive areas. For the remaining five categories, equivalentrequirements have been included directly in or are expected to be developed shortlyunder the City of Long Beach Storm Water Management Plan.

Permittees shall amend codes and promulgate ordinances not later than September 8,2000, to give legal effect to the SUSMP requirements. The SUSMP requirements forprojects identified herein shall take effect not later than October 8, 2000.

DEFINITIONS “100,000 Square Foot Commercial Development” means any commercial developmentthat creates at least 100,000 square feet of impermeable area, including parkingareas.“Automotive Repair Shop” means a facility that is categorized in any one of thefollowing Standard Industrial Classification (SIC) codes: 5013, 5014, 5541, 7532-7534,or 7536-7539.

“Best Management Practice (BMP)” means any program, technology, process, sitingcriteria, operational methods or measures, or engineered systems, which whenimplemented prevent, control, remove, or reduce pollution.

“Commercial Development” means any development on private land that is not heavyindustrial or residential. The category includes, but is not limited to: hospitals,laboratories and other medical facilities, educational institutions, recreational facilities,plant nurseries, multi-apartment buildings, car wash facilities, mini-malls and otherbusiness complexes, shopping malls, hotels, office buildings, public warehouses andother light industrial complexes.


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“Directly Connected Impervious Area (DCIA)” means the area covered by a building,impermeable pavement, and/ or other impervious surfaces, which drains directly intothe storm drain without first flowing across permeable land area (e.g. lawns).

“Discretionary Project” means a project which requires the exercise of judgement ordeliberation when the public agency or public body decides to approve or disapprove aparticular activity, as distinguished from situations where the public agency or bodymerely has to determine whether there has been conformity with applicable statutes,ordinances, or regulations.

“Environmentally Sensitive Area” means an area designated as an Area of SpecialBiological Significance by the State Water Resources Control Board (Water QualityControl Plan, Los Angeles Region: Basin Plan for the Coastal Watersheds of LosAngeles and Ventura Counties (1994) and amendments) or an area designated as anArea of Ecological Significance by the County of Los Angeles (Los Angeles CountySignificant Areas Study, Los Angeles County Department of Regional Planning (1976)and amendments) or an area designated as a significant natural area by the CaliforniaResources Agency. Refer to Table 3 for a listing.

“Greater than (>) 9 unit home subdivision” means any subdivision being developed for10 or more 10 single-family or multi-family dwelling units.

“Hillside” means property located in an area with known erosive soil conditions, wherethe development contemplates grading on any natural slope that is twenty-five percentor greater.

“Infiltration” means the downward entry of water into the surface of the soil.

“New Development” means land disturbing activities; structural development, includingconstruction or installation of a building or structure, creation of impervious surfaces;and land subdivision.

“Parking Lot” means land area or facility for the temporary parking or storage of motorvehicles used personally, for business or for commerce with a lot size of 5,000 squarefeet or more, or with 25 or more parking spaces.

“Redevelopment” means, on an already developed site, the creation or addition of atleast 5,000 square feet of impervious surfaces or the creation or addition of fifty percentor more of impervious surfaces or the making of improvements to fifty percent or moreof the existing structure. Redevelopment includes, but is not limited to: the expansion ofa building footprint or addition or replacement of a structure; structural developmentincluding an increase in gross floor area and/ or exterior construction or remodeling;replacement of impervious surface that is not part of a routine maintenance activity;and land disturbing activities related with structural or impervious surfaces.


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“Restaurant” means a stand-alone facility that sells prepared foods and drinks forconsumption, including stationary lunch counters and refreshment stands sellingprepared foods and drinks for immediate consumption. (SIC code 5812).

“Retail Gasoline Outlet” means any facility engaged in selling gasoline and lubricatingoils.

“Source Control BMP” means any schedules of activities, prohibitions of practices,maintenance procedures, managerial practices or operational practices that aim toprevent storm water pollution by reducing the potential for contamination at the sourceof pollution.

“Storm Event” means a rainfall event that produces more than 0.1 inch of precipitationand that, which is separated from the previous storm event by at least 72 hours of dryweather.

“Structural BMP” means any structural facility designed and constructed to mitigate theadverse impacts of storm water and urban runoff pollution (e.g. canopy, structuralenclosure). The category may include both Treatment Control BMPs and SourceControl BMPs.

“Treatment” means the application of engineered systems that use physical, chemical,or biological processes to remove pollutants. Such processes include, but are notlimited to, filtration, gravity settling, media adsorption, biodegradation, biologicaluptake, chemical oxidation and UV radiation.

“Treatment Control BMP” means any engineered system designed to remove pollutantsby simple gravity settling of particulate pollutants, filtration, biological uptake, mediaadsorption or any other physical, biological, or chemical process.

CONFLICTS WITH LOCAL PRACTICESWhere provisions of the SUSMP requirements conflict with established local codes,(e.g., specific language of signage used on storm drain stenciling), the Permittee maycontinue the local practice and modify the SUSMP to be consistent with the code,except that to the extent that the standards in the SUSMP are more stringent thanthose under local codes, such more stringent standards shall apply.

SUSMP PROVISIONS APPLICABLE TO ALL CATEGORIES


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REQUIREMENTS

1. PEAK STORM WATER RUNOFF DISCHARGE RATES

Post-development peak storm water runoff discharge rates shall not exceed theestimated pre-development rate for developments where the increased peak stormwater discharge rate will result in increased potential for downstream erosion.

2. CONSERVE NATURAL AREAS

If applicable, the following items are required and must be implemented in the sitelayout during the subdivision design and approval process, consistent with applicableGeneral Plan and Local Area Plan policies:

• Concentrate or cluster Development on portions of a site while leaving the remaining land ina natural undisturbed condition.

• Limit clearing and grading of native vegetation at a site to the minimum amount needed tobuild lots, allow access, and provide fire protection.

• Maximize trees and other vegetation at each site by planting additional vegetation, clusteringtree areas, and promoting the use of native and/or drought tolerant plants.

• Promote natural vegetation by using parking lot islands and other landscaped areas.• Preserve riparian areas and wetlands.

3. MINIMIZE STORM WATER POLLUTANTS OF CONCERN

Storm water runoff from a site has the potential to contribute oil and grease, suspendedsolids, metals, gasoline, pesticides, and pathogens to the storm water conveyancesystem. The development must be designed so as to minimize, to the maximum extentpracticable, the introduction of pollutants of concern that may result in significantimpacts, generated from site runoff of directly connected impervious areas (DCIA), tothe storm water conveyance system as approved by the building official. Pollutants ofconcern, consist of any pollutants that exhibit one or more of the followingcharacteristics: current loadings or historic deposits of the pollutant are impacting thebeneficial uses of a receiving water, elevated levels of the pollutant are found insediments of a receiving water and/or have the potential to bioaccumulate in organismstherein, or the detectable inputs of the pollutant are at a concentrations or loadsconsidered potentially toxic to humans and/or flora and fauna.

In meeting this specific requirement, “minimization of the pollutants of concern” willrequire the incorporation of a BMP or combination of BMPs best suited to maximize thereduction of pollutant loadings in that runoff to the Maximum Extent Practicable. ThoseBMPs best suited for that purpose are those listed in the California Storm Water BestManagement Practices Handbooks; Caltrans Storm Water Quality Handbook: Planningand Design Staff Guide; Manual for Storm Water Management in Washington State;


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The Maryland Stormwater Design Manual; Florida Development Manual: A Guide toSound Land and Water Management; Denver Urban Storm Drainage Criteria Manual,Volume 3 – Best Management Practices and Guidance Specifying ManagementMeasures for Sources of Nonpoint Pollution in Coastal Waters , USEPA Report No.EPA-840-B-92-002, as “likely to have significant impact” beneficial to water quality fortargeted pollutants that are of concern at the site in question. However, it is possiblethat a combination of BMPs not so designated, may in a particular circumstance, bebetter suited to maximize the reduction of the pollutants.

Examples of BMPs that can be used for minimizing the introduction of pollutants ofconcern generated from site runoff are identified in Table 2. Any BMP not specificallyapproved by the Regional Board in Resolution No. 99-03, “Approving BestManagement Practices for Municipal Storm Water and Urban Runoff Programs in LosAngeles County”, for development planning may be used if they have beenrecommended in one of the above references.

4. PROTECT SLOPES AND CHANNELS

Project plans must include BMPs consistent with local codes and ordinances and theSUSMP to decrease the potential of slopes and/or channels from eroding andimpacting storm water runoff:

• Convey runoff safely from the tops of slopes and stabilize disturbed slopes.• Utilize natural drainage systems to the maximum extent practicable• Control or reduce or eliminate flow to natural drainage systems to the

maximum extent practicable• Stabilize permanent channel crossings.• Vegetate slopes with native or drought tolerant vegetation.• Install energy dissipaters, such as riprap, at the outlets of new storm drains,

culverts, conduits, or channels that enter unlined channels in accordancewith applicable specifications to minimize erosion, with the approval of allagencies with jurisdiction, e.g., the U.S. Army Corps of Engineers and theCalifornia Department of Fish and Game

5. PROVIDE STORM DRAIN SYSTEM STENCILING AND SIGNAGE

Storm drain stencils are highly visible source controls that are typically placed directlyadjacent to storm drain inlets. The stencil contains a brief statement that prohibits thedumping of improper materials into the storm water conveyance system. Graphicalicons, either illustrating anti-dumping symbols or images of receiving water fauna, areeffective supplements to the anti-dumping message.

• All storm drain inlets and catch basins within the project area must be


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stenciled with prohibitive language (such as: “NO DUMPING – DRAINS TOOCEAN”) and/or graphical icons to discourage illegal dumping.

• Signs and prohibitive language and/or graphical icons, which prohibit illegaldumping, must be posted at public access points along channels and creekswithin the project area.

• Legibility of stencils and signs must be maintained.

6. PROPERLY DESIGN OUTDOOR MATERIAL STORAGE AREAS

Outdoor material storage areas refer to storage areas or storage facilities solely for thestorage of materials. Improper storage of materials outdoors may provide anopportunity for toxic compounds, oil and grease, heavy metals, nutrients, suspendedsolids, and other pollutants to enter the storm water conveyance system. Whereproposed project plans include outdoor areas for storage of materials that maycontribute pollutants to the storm water conveyance system, the following Structural orTreatment BMPs are required:

• Materials with the potential to contaminate storm water must be: (1) placed inan enclosure such as, but not limited to, a cabinet, shed, or similar structurethat prevents contact with runoff or spillage to the storm water conveyancesystem; or (2) protected by secondary containment structures such as berms,dikes, or curbs.

• The storage area must be paved and sufficiently impervious to contain leaksand spills.

• The storage area must have a roof or awning to minimize collection of stormwater within the secondary containment area.

7. PROPERLY DESIGN TRASH STORAGE AREAS

A trash storage area refers to an area where a trash receptacle or receptacles arelocated for use as a repository for solid wastes.

Loose trash and debris can be easily transported by the forces of water or wind intonearby storm drain inlets, channels, and/or creeks. All trash container areas must meetthe following Structural or Treatment Control BMP requirements (individual singlefamily residences are exempt from these requirements):

• Trash container areas must have drainage from adjoining roofs andpavement diverted around the area(s).

• Trash container areas must be screened or walled to prevent off-sitetransport of trash.


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8. PROVIDE PROOF OF ONGOING BMP MAINTENANCE

Improper maintenance is one of the most common reasons why water quality controlswill not function as designed or which may cause the system to fail entirely. It isimportant to consider who will be responsible for maintenance of a permanent BMP,and what equipment is required to perform the maintenance properly. As part of projectreview, if a project applicant has included or is required to include, Structural orTreatment Control BMPs in project plans, the Permittee shall require that the applicantprovide verification of maintenance provisions through such means as may beappropriate, including, but not limited to legal agreements, covenants, CEQA mitigationrequirements and/or Conditional Use Permits.

For all properties, the verification will include the developer’s signed statement, as partof the project application, accepting responsibility for all structural and treatment controlBMP maintenance until the time the property is transferred and, where applicable, asigned agreement from the public entity assuming responsibility for Structural orTreatment Control BMP maintenance. The transfer of property to a private or publicowner must have conditions requiring the recipient to assume responsibility formaintenance of any Structural or Treatment Control BMP to be included in the sales orlease agreement for that property, and will be the owner’s responsibility. The conditionof transfer shall include a provision that the property owners conduct maintenanceinspection of all Structural or Treatment Control BMPs at least once a year and retainproof of inspection. For residential properties where the Structural or TreatmentControl BMPs are located within a common area which will be maintained by ahomeowner’s association, language regarding the responsibility for maintenance mustbe included in the projects conditions, covenants and restrictions (CC&Rs). Printededucational materials will be required to accompany the first deed transfer to highlightthe existence of the requirement and to provide information on what storm watermanagement facilities are present, signs that maintenance is needed, how thenecessary maintenance can be performed, and assistance that the Permittee canprovide. The transfer of this information shall also be required with any subsequentsale of the property.

If Structural or Treatment Control BMPs are located within a public area proposed fortransfer, they will be the responsibility of the developer until they are accepted fortransfer by the County or other appropriate public agency. Structural or TreatmentControl BMPs proposed for transfer must meet design standards adopted by the publicentity for the BMP installed and should be approved by the County or other appropriatepublic agency prior to its installation.

9. DESIGN STANDARDS FOR STRUCTURAL OR TREATMENT CONTROL BMPs

Structural or Treatment control BMPs selected for use at any project covered by this


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SUSMP shall meet the design standards of this Section unless specifically exempted.

Post-construction Structural or Treatment Control BMPs shall be designed to:

A. mitigate (infiltrate or treat) storm water runoff from either:

1. the 85th percentile 24-hour runoff event determined as the maximized capture storm watervolume for the area, from the formula recommended in Urban Runoff Quality Management,WEF Manual of Practice No. 23/ ASCE Manual of Practice No. 87, (1998), or

2. the volume of annual runoff based on unit basin storage water quality volume, to achieve 80percent or more volume treatment by the method recommended in California Stormwater BestManagement Practices Handbook – Industrial/ Commercial, (1993), or

3. the volume of runoff produced from a 0.75 inch storm event, prior to its discharge to a stormwater conveyance system, or

4. the volume of runoff produced from a historical-record based reference 24-hour rainfallcriterion for “treatment” (0.75 inch average for the Los Angeles County area) that achievesapproximately the same reduction in pollutant loads achieved by the 85th percentile 24-hourrunoff event,

AND

B. control peak flow discharge to provide stream channel and over bank floodprotection, based on flow design criteria selected by the local agency.

Limited Exclusion

Restaurants, where the land area for development or redevelopment is less than 5,000square feet, are excluded from the numerical Structural or Treatment Control BMPdesign standard requirement only.

10. PROVISIONS APPLICABLE TO INDIVIDUAL PRIORITY PROJECT CATEGORIES

REQUIREMENTS


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A. 100,000 SQUARE FOOT COMMERCIAL DEVELOPMENTS

1. PROPERLY DESIGN LOADING/UNLOADING DOCK AREAS

Loading/unloading dock areas have the potential for material spills to be quicklytransported to the storm water conveyance system. To minimize this potential, thefollowing design criteria are required:

• Cover loading dock areas or design drainage to minimize run-on and runoff of storm water.• Direct connections to storm drains from depressed loading docks (truck wells) are prohibited.

2. PROPERLY DESIGN REPAIR/MAINTENANCE BAYS

Oil and grease, solvents, car battery acid, coolant and gasoline from therepair/maintenance bays can negatively impact storm water if allowed to come intocontact with storm water runoff. Therefore, design plans for repair bays must includethe following:

• Repair/maintenance bays must be indoors or designed in such a way that doesn’t allow storm waterrunon or contact with storm water runoff.

• Design a repair/maintenance bay drainage system to capture all washwater, leaks and spills.Connect drains to a sump for collection and disposal. Direct connection of the repair/maintenancebays to the storm drain system is prohibited. If required by local jurisdiction, obtain an IndustrialWaste Discharge Permit.

3. PROPERLY DESIGN VEHICLE/EQUIPMENT WASH AREAS

The activity of vehicle/equipment washing/steam cleaning has the potential tocontribute metals, oil and grease, solvents, phosphates, and suspended solids to thestorm water conveyance system. Include in the project plans an area for washing/steamcleaning of vehicles and equipment. The area in the site design must be:

• Self-contained and/ or covered, equipped with a clarifier, or other pretreatment facility, and properlyconnected to a sanitary sewer.

B. RESTAURANTS

1. PROPERLY DESIGN EQUIPMENT/ACCESSORY WASH AREAS

The activity of outdoor equipment/accessory washing/steam cleaning has the potentialto contribute metals, oil and grease, solvents, phosphates, and suspended solids to thestorm water conveyance system. Include in the project plans an area for the


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washing/steam cleaning of equipment and accessories. This area must be:

• Self-contained, equipped with a grease trap, and properly connected to a sanitary sewer.• If the wash area is to be located outdoors, it must be covered, paved, have secondary containment,

and be connected to the sanitary sewer.

C. RETAIL GASOLINE OUTLETS

1. PROPERLY DESIGN FUELING AREA

Fueling areas have the potential to contribute oil and grease, solvents, car battery acid,coolant and gasoline to the storm water conveyance system. The project plans mustinclude the following BMPs:

• The fuel dispensing area must be covered with an overhanging roof structure or canopy. Thecanopy’s minimum dimensions must be equal to or greater than the area within the grade break. The canopy must not drain onto the fuel dispensing area, and the canopy downspouts must berouted to prevent drainage across the fueling area.

• The fuel dispensing area must be paved with Portland cement concrete (or equivalent smoothimpervious surface), and the use of asphalt concrete shall be prohibited.

• The fuel dispensing area must have a 2% to 4% slope to prevent ponding, and must be separatedfrom the rest of the site by a grade break that prevents run-on of storm water to the extentpracticable.

• At a minimum, the concrete fuel dispensing area must extend 6.5 feet (2.0 meters) from the cornerof each fuel dispenser, or the length at which the hose and nozzle assembly may be operated plus 1foot (0.3 meter), whichever is less.

D. AUTOMOTIVE REPAIR SHOPS

1. PROPERLY DESIGN FUELING AREA

Fueling areas have the potential to contribute oil and grease, solvents, car battery acid,coolant and gasoline to the storm water conveyance system. Therefore, design plans,which include fueling areas, must contain the following:

• The fuel dispensing area should be covered with an overhanging roof structure or canopy. Thecover’s minimum dimensions must be equal to or greater than the area within the grade break. Thecover must not drain onto the fuel dispensing area and the downspouts must be routed to preventdrainage across the fueling area.

• The fuel dispensing areas must be paved with Portland cement concrete (or equivalent smoothimpervious surface), and the use of asphalt concrete shall be prohibited.

• The fuel dispensing area must have a 2% to 4% slope to prevent ponding, and must be separatedfrom the rest of the site by a grade break that prevents run-on of storm water.

• At a minimum, the concrete fuel dispensing area must extend 6.5 feet (2.0 meters) from the cornerof each fuel dispenser, or the length at which the hose and nozzle assembly may be operated plus 1foot (0.3 meter), whichever is less.


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2. PROPERLY DESIGN REPAIR/MAINTENANCE BAYS

Oil and grease, solvents, car battery acid, coolant and gasoline from therepair/maintenance bays can negatively impact storm water if allowed to come intocontact with storm water runoff. Therefore, design plans for repair bays must includethe following:

• Repair/maintenance bays must be indoors or designed in such a way that doesn’t allow storm waterrun-on or contact with storm water runoff.

• Design a repair/maintenance bay drainage system to capture all wash-water, leaks and spills.Connect drains to a sump for collection and disposal. Direct connection of the repair/maintenancebays to the storm drain system is prohibited. If required by local jurisdiction, obtain an IndustrialWaste Discharge Permit.

3. PROPERLY DESIGN VEHICLE/EQUIPMENT WASH AREAS

The activity of vehicle/equipment washing/steam cleaning has the potential tocontribute metals, oil and grease, solvents, phosphates, and suspended solids to thestorm water conveyance system. Include in the project plans an area for washing/steamcleaning of vehicles and equipment. This area must be:

• Self-contained and/or covered, equipped with a clarifier, or other pretreatment facility, and properlyconnected to a sanitary sewer or to a permitted disposal facility.

4. PROPERLY DESIGN LOADING/UNLOADING DOCK AREAS

Loading/unloading dock areas have the potential for material spills to be quicklytransported to the storm water conveyance system. To minimize this potential, thefollowing design criteria are required:

• Cover loading dock areas or design drainage to minimize run-on and runoff of storm water.• Direct connections to storm drains from depressed loading docks (truck wells) are prohibited.

E. PARKING LOTS

1. PROPERLY DESIGN PARKING AREA

Parking lots contain pollutants such as heavy metals, oil and grease, and polycyclicaromatic hydrocarbons that are deposited on parking lot surfaces by motor-vehicles.These pollutants are directly transported to surface waters. To minimize the offsitetransport of pollutants, the following design criteria are required:


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• Reduce impervious land coverage of parking areas• Infiltrate runoff before it reaches storm drain system.• Treat runoff before it reaches storm drain system

2. PROPERLY DESIGN TO LIMIT OIL CONTAMINATION AND PERFORMMAINTENANCE

Parking lots may accumulate oil, grease, and water insoluble hydrocarbons fromvehicle drippings and engine system leaks.

• Treat to remove oil and petroleum hydrocarbons at parking lots that are heavily used (e.g. fast food outlets, lots with 25 or more parking spaces , sports event parking lots, shopping malls, grocerystores, discount warehouse stores)

• Ensure adequate operation and maintenance of treatment systems particularly sludge and oilremoval, and system fouling and plugging prevention control

11. WAIVER

A Permittee may, through adoption of an ordinance or code incorporating the treatmentrequirements of the SUSMP, provide for a waiver from the requirement ifimpracticability for a specific property can be established. A waiver of impracticabilityshall be granted only when all other Structural or Treatment Control BMPs have beenconsidered and rejected as infeasible. Recognized situations of impracticability include,(i) extreme limitations of space for treatment on a redevelopment project, (ii)unfavorable or unstable soil conditions at a site to attempt infiltration, and (iii) risk ofground water contamination because a known unconfined aquifer lies beneath the landsurface or an existing or potential underground source of drinking water is less than 10feet from the soil surface. Any other justification for impracticability must be separatelypetitioned by the Permittee and submitted to the Regional Board for consideration. TheRegional Board may consider approval of the waiver justification or may delegate theauthority to approve a class of waiver justifications to the Regional Board ExecutiveOfficer. The supplementary waiver justification becomes recognized and effective onlyafter approval by the Regional Board or the Regional Board Executive Officer. A waivergranted by a Permittee to any development or redevelopment project may be revokedby the Regional Board Executive Officer for cause and with proper notice upon petition.

If a waiver is granted for impracticability, the Permittee must require the projectproponent to transfer the savings in cost, as determined by the Permittee, to a stormwater mitigation fund to be used to promote regional or alternative solutions for stormwater pollution in the storm watershed and operated by a public agency or a non-profitentity.


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12. LIMITATION ON USE OF INFILTRATION BMPs

Three factors significantly influence the potential for storm water to contaminate groundwater. They are (i) pollutant mobility, (ii) pollutant abundance in storm water, (iii) andsoluble fraction of pollutant. The risk of contamination of groundwater may be reducedby pretreatment of storm water. A discussion of limitations and guidance for infiltrationpractices is contained in, Potential Groundwater Contamination from Intentional andNon-Intentional Stormwater Infiltration, Report No. EPA/600/R-94/051, USEPA (1994).

In addition, the distance of the groundwater table from the infiltration BMP may also bea factor determining the risk of contamination. A water table distance separation of tenfeet depth in California presumptively poses negligible risk for storm water notassociated with industrial activity or high vehicular traffic.

Infiltration BMPs are not recommended for areas of industrial activity or areas subjectto high vehicular traffic (25,000 or greater average daily traffic (ADT) on main roadwayor 15,000 or more ADT on any intersecting roadway) unless appropriate pretreatment isprovided to ensure groundwater is protected and the infiltration BMP is not renderedineffective by overload.

13. ALTERNATIVE CERTIFICATION FOR STORM WATER TREATMENTMITIGATION

In lieu of conducting detailed BMP review to verify Structural or Treatment ControlBMPs adequacy, a Permittee may elect to accept a signed certification from a CivilEngineer or a Licensed Architect registered in the State of California, that the planmeets the criteria established herein. The Permittee is encouraged to verify thatcertifying person(s) have been trained on BMP design for water quality, not more thantwo years prior to the signature date. Training conducted by an organization with stormwater BMP design expertise (e.g., a University, American Society of Civil Engineers,American Society of Landscape Architects, American Public Works Association, or theCalifornia Water Environment Association) may be considered qualifying.

14. RESOURCES AND REFERENCE

TABLE 1

SUGGESTED RESOURCES HOW TO GET A COPY


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Start at the Source (1999) by Bay Area StormwaterManagement Agencies Association

Detailed discussion of permeable pavements andalternative driveway designs presented.

Bay Area Stormwater Management AgenciesAssociation2101 Webster StreetSuite 500Oakland, CA510-286-1255

Design of Stormwater Filtering Systems (1996) byRichard A. Claytor and Thomas R. Schuler

Presents detailed engineering guidance on tendifferent storm water-filtering systems.

Center for Watershed Protection8391 Main StreetEllicott City, MD 21043410-461-8323

Better Site Design: A Handbook for ChangingDevelopment Rules in Your Community (1998)

Presents guidance for different model developmentalternatives.

Center for Watershed Protection8391 Main StreetEllicott City, MD 21043410-461-8323

Design Manual for Use of Bioretention inStormwater Management (1993)

Presents guidance for designing bioretentionfacilities.

Prince George’s CountyWatershed Protection Branch9400 Peppercorn Place, Suite 600Landover, MD 20785

Operation, Maintenance and Management ofStormwater Management (1997)

Provides a thorough look at stormwater practicesincluding, planning and design considerations,programmatic and regulatory aspects,maintenance considerations, and costs.

Watershed Management Institute, Inc.410 White Oak DriveCrawfordville, FL 32327850-926-5310

California Storm Water Best ManagementPractices Handbooks (1993) for ConstructionActivity, Municipal, and Industrial/Commercial

Presents a description of a large variety ofStructural BMPs, Treatment Control, BMPs andSource Control BMPs

Los Angeles County Department of Public WorksCashiers Office900 S. Fremont AvenueAlhambra, CA 91803626-458-6959

TABLE 1 (Continued)

SUGGESTED RESOURCES HOW TO GET A COPY


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Second Nature: Adapting LA’s Landscape forSustainable Living (1999) by Tree People

Detailed discussion of BMP designs presented toconserve water, improve water quality, andachieve flood protection.

Tree People12601 Mullholland DriveBeverly Hills, CA 90210818-753-4600 (?)

Florida Development Manual: A Guide to SoundLand and Water Management (1988)

Presents detailed guidance for designing BMPs

Florida Department of the Environment 2600Blairstone Road, Mail Station 3570Tallahassee, FL 32399 850-921-9472

Stormwater Management in Washington State (1999) Vols. 1-5

Presents detailed guidance on BMP design for newdevelopment and construction.

Department of PrintingState of Washington Department of EcologyP.O. Box 798Olympia, WA 98507-0798360-407-7529

Maryland Stormwater Design Manual (1999)

Presents guidance for designing storm water BMPs

Maryland Department of the Environment2500 Broening HighwayBaltimore, MD 21224410-631-3000

Texas Nonpoint Source Book – Online Module(1998)www.txnpsbook.org

Presents BMP design and guidance informationon-line

Texas Statewide Storm Water Quality Task ForceNorth Central Texas Council of Governments616 Six Flags DriveArlington, TX 76005817-695-9150

Urban Storm Drainage, Criteria Manual – Volume3, Best Management Practices (1999)

Presents guidance for designing BMPs

Urban Drainage and Flood Control District2480 West 26th Avenue, Suite 156-BDenver, CO 80211

303-455-6277

Guidance Specifying Management Measures forSources of Nonpoint Pollution in Coastal Waters(1993) Report No. EPA–840-B-92-002.

Provides an overview of, planning and designconsiderations, programmatic and regulatoryaspects, maintenance considerations, and costs.

National Technical Information Service U.S.Department of CommerceSpringfield, VA 22161800-553-6847

National Stormwater Best Management Practices(BMP) Database, Version 1.0

Provides data on performance and evaluation ofstorm water BMPs

American Society of Civil Engineers1801 Alexander Bell DriveReston, VA 20191703-296-6000


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SUGGESTED RESOURCES HOW TO GET A COPYCaltrans Storm Water Quality Handbook: Planningand Design Staff Guide (Best ManagementPractices Handbooks (1998)

Presents guidance for design of storm water BMPs

California Department of TransportationP.O. Box 942874Sacramento, CA 94274-0001916-653-2975


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TABLE 2

EXAMPLE BEST MANAGEMENT PRACTICES (BMPs)

The following are examples of BMPs that can be used for minimizing the introduction ofpollutants of concern that may result in significant impacts, generated from site runoff tothe storm water conveyance system. (See Table 1: Suggested Resources for additionalsources of information):

• Provide reduced width sidewalks and incorporate landscaped buffer areas betweensidewalks and streets. However, sidewalk widths must still comply with regulations for theAmericans with Disabilities Act and other life safety requirements.

• Design residential streets for the minimum required pavement widths needed to comply withall zoning and applicable ordinances to support travel lanes; on-street parking; emergency,maintenance, and service vehicle access; sidewalks; and vegetated open channels.

• Comply with all zoning and applicable ordinances to minimize the number of residentialstreet cul-de-sacs and incorporate landscaped areas to reduce their impervious cover. Theradius of cul-de-sacs should be the minimum required to accommodate emergency andmaintenance vehicles. Alternative turnarounds should be considered.

• Use permeable materials for private sidewalks, driveways, parking lots, or interior roadwaysurfaces (examples: hybrid lots, parking groves, permeable overflow parking, etc.).

• Use open space development that incorporates smaller lot sizes.• Reduce building density.• Comply with all zoning and applicable ordinances to reduce overall lot imperviousness by

promoting alternative driveway surfaces and shared driveways that connect two or morehomes together.

• Comply with all zoning and applicable ordinances to reduce the overall imperviousnessassociated with parking lots by providing compact car spaces, minimizing stall dimensions,incorporating efficient parking lanes, and using pervious materials in spillover parking areas.

• Direct rooftop runoff to pervious areas such as yards, open channels, or vegetated areas,and avoid routing rooftop runoff to the roadway or the storm water conveyance system.

• Vegetated swales and strips• Extended/dry detention basins• Infiltration basin• Infiltration trenches• Wet ponds • Constructed wetlands• Oil/Water separators• Catch basin inserts• Continuous flow deflection/ separation systems• Storm drain inserts• Media filtration• Bioretention facility• Dry-wells• Cisterns• Foundation planting• Catch basin screens• Normal flow storage/ separation systems• Clarifiers• Filtration systems• Primary waste water treatment systems


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TABLE 3

HABITAT PROTECTION IN THE LOS ANGELES COUNTY AREA

Agency:State Water Resources Control Board

Designation:Areas of Significant Biological Significance (ASBS)

Definition:Areas designated by the State Water Resources Control Board as requiring protection of species orbiological communities to the extent that alteration of natural water quality is undesirable.

Affected Area:(See Table 1 & Figure 2)

Agency:Los Angeles County Department of Regional Planning

Designation:Significant Ecological Areas (SEA)

Definitions:Significant Ecological Areas (SEAs) are areas that have been identified by the Los Angeles CountyGeneral Plan as containing unique or unusual species assemblages, or areas of habitat that are rapidlydeclining in the Los Angeles County. The SEAs were established to protect a special or sometimesunique collection of habitats and species from loss due to encroachment and human disturbances.However, SEAs are not intended to function as isolated preservation areas.

Affected Areas:(See Table A & Figure 1)

Agency:California Department of Fish & Game

Designation:Natural Communities Conservation Plan Region (NCCP)

Definition:Identifies and provides for the regional or area wide protection and perpetuation of natural wildlifediversity, while allowing compatible and appropriate development and growth. The goal of the programis to protect sufficient resources in regional preserves to assure the survival of the ecosystem and, at thesame time, permit compatible uses of less sensitive land.

Affected Area:(See Table 1 & Figure 3)


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TABLE 3 A

HABITAT PROTECTION IN LOS ANGELES COUNTY AREA1

Figure 1 AFFECTED AREA DESIGNATION DESIGNATING AGENCY 1. Malibu Coastline SEA LACDRP 2. Point Dume SEA LACDRP 3. Zuma Canyon SEA LACDRP 4. Upper La Sierra Canyon SEA LACDRP 5. Malibu Canyon and Lagoon SEA LACDRP 5. Malibu Creek State Park Buffer Area SEA LACDRP 6. Las Virgenes SEA LACDRP 7. Hepatic Gulch SEA LACDRP 9. Cold Creek SEA LACDRP10. Tuna Canyon SEA LACDRP11. Temescal-Rustic-Sullivan Canyons SEA LACDRP12. Palo Comado Canyon SEA LACDRP13. Chatsworth Reservior SEA LACDRP14. Simi Hills SEA LACDRP15. Tonner Canyon/Chino Hills SEA LACDRP16. Buzzard Peak/ San Jose Hills SEA LACDRP17. Powder Canyon/Punte Hills SEA LACDRP18. Way Hills SEA LACDRP19. San Francisquito Canyon SEA LACDRP20. Santa Susana Mountains SEA LACDRP21. Santa Susana Pass SEA LACDRP22. Santa Fe Dam Floodplain SEA LACDRP23. Santa Clara River SEA LACDRP24. Tujunga Valley/Hansen Dam SEA LACDRP25. San Dimas Canyon SEA LACDRP26. San Antonio Canyon Mouth SEA LACDRP27. Portuguese Bend Landslide SEA LACDRP28. El Segundo Dunes SEA LACDRP29. Ballona Creek SEA LACDRP30. Alamitos Bay SEA LACDRP31. Rolling Hills Canyons SEA LACDRP32. Agua Amarga Canyon SEA LACDRP33. Terminal Island SEA LACDRP34. Palos Verdes Peninsula Coastline SEA LACDRP35. Harbor Lake Regional Park SEA LACDRP36. Madrona Marsh SEA LACDRP37. Griffith Park SEA LACDRP39. Encino Reservoir SEA LACDRP40. Verdugo Mountains SEA LACDRP

1 This list is a compilation of data from the Department of Fish & Game, State Water Resources Control Board, and the Los AngelesCounty Department of Regional Planning as of February 29, 2000. Areas in this may changes, as area are added or deleted by thedesignating agencies.


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AFFECTED AREA DESIGNATION DESIGNATING AGENCY42. Whittier Narrows Dam County

Recreation AreaSEA LACDRP

43. Rio Hondo College Wildlife Santuary SEA LACDRP44. Sycamore and Turnbull Canyons SEA LACDRP45. Dudleya Densiflora Population SEA LACDRP62. Galium Grande Population SEA LACDRP63. Lyon Canyon SEA LACDRP64. Valley Oaks Savannah, Newhall SEA LACDRPFig.2 Point Dume to Latigo Point ASBS SWRCBFig.3 Palos Verdes Peninsula NCCP DFG


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FIGURE 1


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FIGURE 2


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FIGURE 3

Documents

STANDARD URBAN STORM WATER MITIGATION PLAN FOR LOS ANGELES ... · Area of Ecological Significance by the County of Los Angeles (Los Angeles County Significant Areas Study, Los Angeles